Luminous tube



EXXMINER m: QOAIlNG on PLASTIC moss REFERENCE cowosmous,

I March 24, 1931. J. E. GROSS 'LUMINOUS TUBE Filed June 28, 1929 lllllllll llll ll lllll I: II

INVENTOR Joseph E 6/1255.

BY ATTORNEY Patented Mar. 24, 1931 4 I JOSEPH E. GROSS, F SWISSVALE, PENNSYLVANIQ.

Q Luminous TUBE l ucationmea June as, 1929. Serial No. 374,863.

My invention relates to electrically operated gas filled luminous tubes and more particularly to the electrodes'used in'such tubes;

It is the object of my invention, in general, to provide a luminous tube with electrodes that shall be simple and eificint in operation and capable of being readily and economically manufactured, installed and operated.

A more specific object of my invention is to 19 provide a luminous tube with electrodes that will operate efl'ectively with a minimum amount of sputtering,

Another object of my invention is to provide a gas filled luminous tube that willoperate with a low energy loss at the electrode, thereby resulting in cool running electrodes and thus causing the tube to'have a long life.

A further object of my invention is to provide a gas filled luminous tube with electrodes that may be constructed without the necessity ,ofksintering them prior to placing them in the 'tu e. i a v It is also an object of my invention toprovide a gas filled luminous tube with electrodes that do not have to be cured in the usual manner and which are easily commercially outgassed. p

Other objects of my invention will, in part,

be obvious and will, in part, appear hereincup '10 to form the bod 1% of the electrode. so

after.

Fora better understanding of my invention,treference may be had to the accompanying drawing illustrating one of the various forms my invention may take, in which- Figure 1 is a view, in side elevation, of a luminous tube provided with electrodes constructed in;accordan ce with my invention;

Fig. 2 is an enlarged view, in section of one of the electrodes embodied in the tube illustrated in Fig. 1.

In the drawing, I have illustrated aluminous tube as comprisin an elongated sealed glass envelope 1 that 13 adapted to be exhausted of air and ases to a predetermined value and then fill with a monatomic gas,

such as neon, argon or helium.

The glass envelope 1 is shownas having enlarged end portions 2 and 3 iniwhich are disposed, respectively, electrodes 4 and 5 that may be connected to a suitable source of powsoluble silicate, such as otassium silicate or sodium s l cate, preferably sod1um silicate,

er such as the secondary circuit of a transformer 6 by a pair of lead-in wires 7 and 8.

Inasmuch as each of the electrodes 4 and 5 is constructed in the same manner, a detailed description of only one 'of them will be given.

' The electrode 4 is disposed on a supportin member 9 of a suitable insulatin materia suchas glass. The upper part 0 the supporting member 9 is provided with a cup shaped portion 10 for holding the electrode in position and its lower part is mounted on and fused to a glass press 11 that constitutes a part of the glass envelope 1. Connected to the electrode is a conductor 12 that passes downwardly through the stem of the supporting 55 member 9 and serves to connect the electrode to its lead-in wire in the press 11.

In constructing the electrode, I take a suitmtrate and add thereto a sufliciently conductable portion of bagp'um nitrate, strontium ni- I te or titani mn rate pre erahly titanium 7o 82 ing material such as a metal whose oxide is "conducting or a conductln oxide, or a finely divided carbon, pre era y ra hite (say from 5% to 50% by weight) to cause Elie mixture to be semi-conducting. This material is then placed in a mortar and worked until it is a thoroughly mixed powder. The resulting mixture is now placed in the next take a suita e portion of a water and dilute it with water to somewhere under 10% and then lace a drop of the resultin 8 solution u pgn FiF't'jiBfjfhE -iiii iitiii"?? 131% The dro 14 of the solution of silicate may be mixe into the top portion of the powder 13 by a ,wire or other suitable implement and in some cases it may be necessary to add another drop of the solution to the powder to insure a complete coverin When the solution of silicate 14 is lace on the powder 13, a'chemical action ta es place that causes the top dressing to form a highly insoluble and cementive silicate that retains the powder and the silicate in position on the sup orting member 9. The electrode is now read; to be inserted in the glass envelope 1.

. terin and t eJpressure has The electrodes 4 and 5 are now assembled in the lam tube, the lamp is connected to the pumps not shown) in t e usual manner to be evacuated and the lead-in wires are connected to the transformer 6. When the lamp is connected to the transformer it "is supplied with a low volta e of from 5000 to 9000 volts.

After sugcient gas is withdrawn from the tube by the 'pum s so that the pressure the neighborho of one millimeter of cury, a discharge takes electrodes 4 and 5. This 7 the" glass tube-1 and the electrodes 4 and 5, thereby causing gasses to be evolved at the electrodes and also removed from the inner' surface of the tube. As the evacuation pro-. ceeds, the electrodes become hotter and, fin- I ally, when the gasses are practically removed from them, they become red hot.

At this stage of the operation, practically all ofthe injurious gasses have n removed fromthe electrodes, a certain amount of sinhas also taken 'is in merplace between the place in the electrodes, dropped to a-value of less than one tenth of a millimeter of mera cury, probably in the nature of one hundreth 4 ofa millimeter. When the tube reaches .the

cooling for the purpose of removing the last condition just described from its source of electrical energy and allowed to cool, but it is left on the pump while traces of gas. After the gas is completel removed,'a supply of a monatomic gas, as neon is allowedto flow into the .tube to a pressure of from two to three millimeters and the lamp is again connected to its source of electrical energy indicated by the transformer 6. Sufiic1ent current is now causedto flow from the transformer to cause the,

and the-lam .soon as the amp becomes sli htlycooled," a supply of fresh neon gas is '5 into the tube to a qpressure..of; from 6 as 8 electrodes 4 and 5 andthe tube 1 to become.

After the lamp has become quite hot, the I neon gas in the tube is completel evacuated is allowed to cool s ightly." As

lowed to flow.

inillimeters'and-the tube is then sealed off the pump. Following this, the tube is-placed on an ageing rackin the usual manner and al With a lamp electrodes is lowe to age until all the harmful gasses are removed in the around the lamp is ready for constructed this manner, I it will be found that the discharge from the centered at a comparatively small area, and that this area becomes so hot that practically-all the electrical discharge takes place from that one spot, its action being comparable .to thatof an arc, thereby glow type orm little or no' film on its interior surface.

avoiding practically. any discharge of the and providing a tube that will It will therefore be seen that I have proi vided a tube with'electrodes that are easily discharge heats both it is disconnected 4,.

1,7e7,ees

While I have illustrated and described only one specific embodiment of my invention, I realize that it is susceptible of wide application, and I do'not desire to be limited to the precise construction illustrated and described. a

I claim as my invention:

1. An electrode for luminous tubes comprising a body covered with onl a water soluble silicate.

of a semi-conducting material I '2. 'An electro e for luminous tubes comprising abody of a semi-conducting material covered with onl a sodium silicate.

3. An electro e for luminous tubes com-' prising a mixture of a metallic nitrate, a conducting material and a water soluble Sllicate.

'4. An electrode for luminous tubes comrising a mixture of a metallic nitrate, a conducting material and sodium silicate.

5. An electrode for luminous tubes comrising a mixture of titanium nitrate, finely 'vided carbon and sodium silicate.-

prising a mixture of a metallic nitrate and a conducting material covered with a water soluble sihcate.

6. An electrode for luminous tubes co 7. An electrode for luminous tubes com- I prising a mixture of a metallic nitrate and a conducting material covered with sodium silicate. I

8,. electrode for luminous tubes comprisin a mixture of titanium nitrate and graphitecovere'd with sodium silicate.

9. An electrode for luminous tubes com: prising a metallic nitrate, a conducting material and potassium silicate.

' 10. The method of making an electrode for a luminous tube comprising mixing a metallic nitrate powder wit a conducting powder,

lacing the mixture on a su porting mem her, covering the mixture wit a water solu' ble silicate, placing the supporting member with the material thereon in a tube, and treating the tube with electrical energy until the material on the supporting member becomes a solid mass.

' In testimony whereof, I have hereunto subscribed my name this 25th da of June, 1929.

J OSEP E. GROSS. 

